<!DOCTYPE html>
<html>
<head>
	<meta charset="utf-8">
	<title>全部变量的声明</title>
</head>
<body>

<script type="text/javascript">
	a = 6;
    function test(){
      b = 3;
      console.info(b)
      console.info(window.b)
    }
    console.info(a)
    console.info(c) // Error c is not defined
    test()
</script>
</body>
</html>